Compression springs manufactured from elastomer materials are well known in the art. Rather than being curved, however, such springs typically have a cylindrical shape and are directed to applications requiring very high spring rates for absorbing substantial quantities of energy in applications such as associated with the railcar industry. In addition, such known springs are designed to absorb energy directed axially against one or both ends of the spring.
Elongated compression springs which are curved have broad and varied applications. They can be used singularly or in combination relative to each other to absorb energy. Typically, with this type of spring, the load is generally applied to an apex of the curved spring and one or both of the longitudinally spaced ends thereof are confined against longitudinal expansion.
It can be beneficial if the spring can be adjusted to affect the spring rate. It is difficult to predict the exact conditions and stresses to which such a spring will be subjected. The fatigue life of most curved springs, however, is generally limited, thus, increasing the required maintenance of the apparatus with which the spring is arranged in operable combination.
Depending upon their application, most curved springs are loaded not only vertically but also by horizontal forces and torques in the longitudinal vertical and transverse vertical planes. Such forces can be generated in several different modes of operation which, again, are highly dependent upon the particular spring application. Such horizontal forces and torques, however, have been known to cause the curved spring to assume an “S” shaped configuration, a phenomena commonly referred to as “S-ing.” The stresses induced in the spring when this occurs can be quite high. To minimize “S-ing” in a curved spring, the stiffness of the spring has been known to be increased. This can, however, detrimentally affect spring performance.
In view of the above, and in accordance with the present invention, there is a continuing need and desire for an elongated compression spring having an arcuate shape between opposed longitudinally spaced ends of the spring.